Door operation and control

摘要

682,518. Control of motors. NATIONAL PNEUMATIC CO. Nov. 4,1949 [Nov. 4,1948], 28340/49. Class 38 (iii) [Also in Groups XXV and XXXV] The doors of a motor vehicle are operated by a series-wound electric motor controlled by a circuit comprising a magnetic relay adapted to reverse the direction of current flow through the armature winding, and switches 60, 62, 64 actuated by rotary cams driven from the door operating linkage for effecting automatic variation in the motor operating speed. In the closed position of the door a hand operated switch 751 is open, the armature members 74, 75 of the relay make contact with terminals 76, 77 respectively, switches 60, 62 are open and switch 64 is closed. Current thus flows through the field winding 16, a resistance 81 and the armature winding 52,53 from brush 51 to brush 50, the motor developing sufficient torque to hold the door closed. On switch 751 being closed, the relay coil 73 is energised to move the members 74, 75 into contact with terminals 78, 79 respectively. Current then flows through the field winding, switch 64 and the armature winding from brush 50 to brush 51 to operate the motor in the door opening direction. Switch 62 closes when the doors have turned through 10 degrees, and, at 67¢ degrees turning, switch 60 closes to shunt the armature through a resistance 71, thus reducing the speed of the motor. At 85 degrees turning switches 60 and 64 open to put a resistance 82 in series with the armature, the doors encountering stops at 90 degrees, when current continues to flow and the motor develops sufficient torque to hold the doors open. Closing movement is initiated by opening the switch 751, current then flowing through switch 62. The latter opens 10 degrees before the doors reach their closed position to put resistance 81 in series with the armature. Since the latter is shunted throughout the closing movement by a resistance 72, the doors close at a speed which is lower than their speed of opening.